Yep, its your body telling you that you're ready to step it down!
Rule of thumb is since you get a LOT more intake using RDA's than with tanks, is to halve the mg/ml in your juice. I use 6mg on my tanks no problem, but dripping 6mg on my mephisto or mutation will get me feeling like I need to hold on to something. LOL.
4-3mg is enough for me on drippers, especially with micro/nano coils. Some people go lower!
If you ever get this feeling again, open your coffee can and take a big inhale; followed by a glass of water. The coffee increases your blood flow temporarily which metabolizes the nicotine faster, and the water washes it off your internal linings.
Hope this helps!